QT:{{"
That something is called quantum key distribution (QKD). The technique
transmits photons in particular quantum states to generate a secure
cryptographic key, with which you can encrypt data sent over an
ordinary, non-quantum connection. QKD is far more secure than standard
cryptography, which relies on hard mathematical problems that can
theoretically be cracked, given enough computing power. Any attempt to
intercept a quantum key, however, will disturb the photon’s quantum
states, alerting users not to use the key (see "Unbeatable security")."}}